Engineer s air-brake valve



(No Model.)

R. E. MARSHALIJIM BNGINBBRS AIR BRAKE VALVE. No. 441,432. Patented Nov.25.1890.

.HMAH

UNiTED STATES:

PATENT OFFICE.

ROBERT E. MARSHALL, OF VILMINGTON, DELAWARE.

ENGINEERAS AIR-BRAKE VALVE.

SPECIFICATION-forming part of Letters Patent N o. 441,432, datedNovember 25, 1890.

Application filed May 1, 1890.

To all whom t my concern,.-

Be it known that I, ROBERT E. MARSHALL, of Wilmington, county of NewCastle, State of Delaware, have invented a certain new and usefulImprovement in Engineers Air-Brake Valves, of which the following is atrue and accurate description, reference being had to the drawings,which form a part of this specification. l

My invention relates to the air-brake sys- 'tem of railway-trains, andespecially to what is generally known as the engineers brakevalve, myobject being to provide a simple and inexpensive brake-valve by which agradual escape of air from the train-pipe will take place in makingservice stops and a rapid escape in making emergency stops.

The. nature of my invention will be bestunderstood as described inconnection with the drawings, in which it is illustrated, and the novelfeatures which I desire to protect by Letters Patent are hereinafterpointed out in the claim.

`In the drawings, Figure l is a side view of part of a train equippedwith the air-brake system; Fig. 2, an elevation of my improved valvewith the casing shown in section; Fig. 3, a transverse section throughmy valve on the line X X of Fig. 2, and Fig. .4 a similar sectionshowing the plug turned in the proper position for making service stops.

A is the locomotive; B, the tender; C, a oar. D is the pump ot' theair-compressor; E, the air-compressor; F, a pipe leading from thecompressor to the main reservoir, which is marked G; H, a pipe leadingfrom the main reservoir to the engineers brake-valve I g J, a pipeleading from the brake-valve to the train or brake pipes, (indicated bythe letters J J K K indicate couplings in the train-pipe. jj arebranches connecting the train-pipe with the auxiliary cylinders L L. Allthese parts, with the exception of the engineers brakevalve, are ofordinary and well-known construction and are used with the ordinaryauxiliary mechanism, brake-cylinders, the., which are not shown in thedrawings, as they form no essential part of my present invention, and Imay here state that my device is as well adapted for use with what isknown as the Westinghouse quick-acting brake as with Serial No.3,501134. (No model.)

the older and better known types of brake mechanism. A

Referring now to the engineers brake-valve, it consists, as shown, of acasing M, in which are formed ports m m', connecting, respectively, withthe train-pipe or a pipe leading to it and with the pipe leading fromthe main reservoir. A third port m2, is formed in the casing for theexhaust. In the casing a plug N is secured in any convenient way. Thisplug is provided with a port n, adapted to connect lthe ports m and m inthe casing, as shown in Fig. 3. A third port 'n' is formed in the plugand leads into the port n at such an angle that when the plug is turnedso that one end of port n will fully register with port m2 the port nwill register with the port m, leading to the train-pipe. On the inside'of port HQI form a small auxiliary port a2. Said port, which whencompared with the port n may be called a notch, is arranged so that itwill register with the port m leading to the train-pipe, when the end ofport n has partially passed the edge of port m2. (See Fig. et.) The topof the plug N, as shown in the drawings, is square at 0, and a handle Ois connected with it, as shown in the drawings.

The operation of my device will be at once understood.: The normalposition of the plug is .that shown in Fig. 3. The main reservoir andtrain-pipe being thus connected together, when it is desired to make aservice stop the engineer turns the plug N to the position indicated inFig. 4, causing the auxiliary port n2 to register with the port n andopen a passage from the train-pipe to the exhaust-port m2, while at thesame time all connection with the main reservoir is cut off. The size ofthe auxiliary port is such as will permit a properly-graduated escape ofair from the trainpipe to eiect an application of the brakes with theordinary promptness required for service stops. When i or any reason itis desired to make a very quick stop, the engineer turns the plug sothat its port n will fully register with the port m, while at the sametime the exhaust-port m2 is fully opened. The air then IOO course beindicated to the engineer by any ofthe usual means-notches,apointer,alatch, or any other convenient device.

The chief merit which I claim for my invcntion is its exceedingsimplicity of construction, whereby it is at once cheap and less likelyto get out of order than the more coinplicated devices heretofore usedto effect sim ilar results.

Having now described my invention, what I claim as new, and desire toprotect by Letters Patent, is-

In combination with the pipes or conduits leading from the mainreservoir of an airbrake apparatus to the train or brake pipe, anengineers brake-valve I, consisting ot' a R. E. MARSHALL. Witnesses'.

LEWIS R. DICK, 'FRANCIS F. CHAMBERS.

